The Greek philosopher, scientist, and religious teacher Pythagoras developed a school of thought that accepted the passage of the soul into another body and established many influential mathematical and philosophical theories.

Mu'ammar al-Qadhafi led the revolution that set up the Libyan republic in 1969. His dream was to unite all Arab lands and create a system of "government by the masses." However, by encouraging and helping provide funds for terrorist activities (the activities of people who use violence to try to get what they want) against Israel and its allies, he became an enemy of many countries throughout the world.

The English statesman Sir Walter Raleigh was also a soldier, explorer, and a man of letters (a distinguished writer). As a champion of overseas expansion into the New World, Raleigh was a victim of mistrust and Spanish hatred.

Sri Ramakrishna was an Indian mystic (one whose religious beliefs are based on spirituality and practices outside of traditional religion), reformer, and saint who, in his own lifetime, came to be hailed by people of all classes as a spiritual embodiment (taking on the physical form) of God.

The American labor and civil rights leader A. Philip Randolph, considered the most prominent of all African American trade unionists, was one of the major figures in the struggle for civil rights and racial equality.

Harun al-Rashid became the fifth caliph (religious and political leader of an Islamic state) of the Abbasid dynasty (ruling family) in September 786 at the age of twenty. During his reign the power and prosperity of the dynasty was at its height, though it has also been argued that its decline began at that time.

Beginning as a radio sports announcer, Ronald Reagan enjoyed success as a movie actor and television personality before beginning a political career. After two terms as governor of California (1967–1975), he defeated Democrat Jimmy Carter (1924–) for the presidency in 1980 and was re-elected in 1984.

The German-born American author Erich Maria Remarque was a popular novelist whose All Quiet on the Western Front, describing the soldier's life in World War I (1914–18; a war involving Germany, Austria-Hungary, and Turkey on one side, and Great Britain, France, Russia, Italy, Japan, and the United States on the other), was a best-seller.

Rembrandt was one of the most important artists of the great age of Dutch painting. In range, originality, and expressive power, his large production of paintings, drawings, and etchings has never been surpassed.

Janet Reno was the seventy-fifth attorney general of the United States and the first woman ever to serve as attorney general, the nation's top law-enforcement job. She sought new frontiers for the Justice Department, which is led by the attorney general and is a powerful force for creating social change.

The French painter Pierre Auguste Renoir was one of the central figures of the impressionist movement (a French art movement of the second half of the nineteenth century whose members sought in their works to represent the first impression of an object upon the viewer). His work is characterized by a richness of feeling and a warmth of response to the world and to the people in it.

Paul Revere is remembered for his ride to warn fellow American patriots of a planned British attack before the Revolutionary War (1775–83), the war fought by Americans to gain independence from England. He was also a fine silversmith (a person who makes objects out of silver) and a master engraver (a person who cuts designs onto things such as metal or wood).

The English businessman and financier Cecil Rhodes founded the modern diamond industry and controlled the British South Africa Company, which acquired Rhodesia and Zambia as British territories. He was also a noted philanthropist (working for charity) and founded the Rhodes scholarships.

Sally Ride is best known as the first American woman sent into outer space, and she is also the youngest person ever sent into orbit. She has received numerous medals and honors for her work as an astronaut, and for her commitment to educating the young.

The German film director Leni Riefenstahl achieved fame and notoriety for her film Triumph of the Will, which critics believed to be propaganda, or material created to spread beliefs, of Adolf Hitler's (1889–1945) army, the Third Reich.

Cal Ripken Jr. holds many records in professional baseball, but it is his breaking of Lou Gehrig's (1903–1941) record of 2,131 consecutive games played that gained him so many admirers, who call him the "Iron Man" of baseball.

Maximilien de Robespierre was the leading voice of the government that ruled France during the French Revolution. He was largely responsible for the Reign of Terror, in which thousands of suspected French traitors were executed.

John D. Rockefeller, an American industrialist (a person who owns or oversees an industrial corporation) and philanthropist (a person who works to help mankind), founded the Standard Oil Company, the University of Chicago, and the Rockefeller Foundation.

The French sculptor Auguste Rodin created his sculptures largely as volumes existing in space, as materials to be controlled for a variety of surface effects. By doing this he anticipated the aims of many twentieth-century sculptors.